Irreversible electroporation (IRE) is a non-thermal, minimally invasive surgical technique to ablate undesirable tissue, for example, tumor tissue. The technique is easy to apply, can be monitored and controlled, is not affected by local blood flow, and does not require the use of adjuvant drugs. The minimally invasive procedure involves placing needle-like electrodes into or around a targeted tissue area to deliver a series of short and intense electric pulses that induce structural changes in the cell membranes that promote cell death.
Another technique for ablating a desired target tissue is radiofrequency ablation (RFA). This procedure involves using an imaging guidance system such as ultrasound (US), computed tomography (CT), or magnetic resonance (MR). During this procedure, a physician places a probe directly into a target tissue area, such as a tumor. Using an energy source, a physician or other practitioner can then deliver a carefully-controlled amount of energy to flow through the electrodes into the tissue which causes the tissue to heat up. The heating is sustained for a predetermined length of time, usually just a few minutes, which kills and destroys the target tissue. RFA procedures can be percutaneously or laparoscopically performed.
Among the problems associated with current IRE procedures is that with current single IRE probe electrode designs, it is common practice for physicians to perform multiple overlapping or stacked ablations. In between each ablation, the physician has to reposition the probes. During this repositioning or pull-back process, however, it is sometimes difficult for physicians to keep all of the probes parallel for ablations that are performed after the first ablation. In addition, it is difficult to know exactly where the first ablation ends and how much overlap there is between successive ablations, which can increase the chances of missing portions of a target tumor tissue between the ablations or may result in unusual or unpredictable ablation shapes.
Another problem that sometimes occurs with current single IRE or RF ablation probes is probe migration. This occurs when an ablation probe moves slightly from the original position where the probe was inserted, either during the placement of additional probes or during an actual ablation procedure. When this occurs, an undertreated area of target tissue can potentially be left behind, or unintended target tissue can be ablated, or alternatively, a vital organ or structure can be damaged by the tip of a needle.
There exists a need in the art for an improved ablation probe and method of using such a probe for improved IRE and RF ablations that will allow a practitioner to more easily predict and control the location and size of IRE and RF ablations and provide the ability to easily maintain the electrodes in a stationary position within tissue before, during, and after an ablation. An electrode probe and method has not yet been proposed that would solve the problems described above, thereby avoiding many of the negative side effects of the current devices described above.
It is a purpose of the invention described herein to provide a dual probe device in which each probe has at least two electrode regions that can be switched between an active energy delivery state and a non-active non-energy delivery state, depending in the desired ablation zone(s), during either IRE or RF ablations.
It is also a purpose of this invention to provide various anchoring means at the distal tip of the ablation probe described herein in order to anchor at least portion of an active portion of the probe(s) relative to a patient's tissue throughout an ablation procedure.
It is also a purpose of this invention to provide an ablation probe that incorporates a means of adjusting the active portion of the electrode axially along the trocar, or the ablation probe may incorporate a plurality of fixed active portions along the trocar in order to allow the user to create multiple ablations along a specific controlled path through a lesion without repositioning the ablation device.
Various other objectives and advantages of the present invention will become apparent to those skilled in the art as more detailed description is set forth below. Without limiting the scope of the invention, a brief summary of some of the claimed embodiments of the invention is set forth below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention can be found in the Detailed Description of the Invention.